There is some increasing interest and an increasing number of encryption offers, or plans to offer encryption, around SIP trunking. Nonetheless, willingness to pay for encryption is not very high and encryption is not seen as really critical. Besides, some technical and legal complications exist. One major limitation is that encryption is never possible across various networks and carriers. Finally, there are alternatives to the providers’ own services, e.g. existing dedicated E-SBCs, at least for large enterprises’ internal communications, so that real willingness to pay may be limited to some midsized companies as well as some public sector organisations. So even if much revenue should not be expected from encryption services, at least these help marketing and can reassure all customers by stressing the security credentials of the SIP trunking provider.